1. Technical Field
Coated surgical sutures having improved antimicrobial properties and a method for using these sutures are described. More particularly, surgical sutures coated with fatty acid esters such as sodium stearoyl lactylate and/or other non-silver stearoyl lactylates in an effective antimicrobial amount are described herein.
2. Background of Related Art
Synthetic absorbable multifilament sutures are well known in the industry. Examples of these sutures include Dexon, Vicryl, and Polysorb, commercially available from Ethicon, Inc. (Somerville, N.J.), and United States Surgical Corporation (Norwalk, Conn.).
It is known that suture materials are often coated with various substances to improve their handling characteristics. For example, U.S. Pat. Nos. 5,123,912, 4,080,969, 4,043,344, 4,047,533, and 4,027,676 disclose coated surgical sutures with improved knot tie down properties.
Suture coatings containing esters of fatty acids are also known. For example, U.S. Pat. No. 5,716,376 discloses suture coatings made of a mixture of fatty acid esters, including calcium stearoyl lactylate, with a copolymer containing caprolactone. The coatings taught by this patent are used for absorbable sutures and other surgical articles and, in the case of sutures, impart improved properties to the suture, such as knot security, surgeon's throw, lubricity, knot run down, and/or knot repositioning. U.S. Pat. No. 4,711,241 discloses suture coatings that include oleyl lactylates containing alkaline earth ions or radicals, with a preferred embodiment consisting of calcium stearoyl-2-lactylate. U.S. Pat. No. 5,032,638 discloses a suture coating comprising a copolymer of poly (Beta-hydroxybutyrate) and a stearoyl lactylate containing alkaline-earth metals, and notes that calcium stearoyl lactylate and magnesium stearoyl lactylate can be added as lubricants. Similarly, U.S. Pat. No. 4,705,820 discloses a suture coating comprising a random copolymer and a lubricant, which can be a stearoyl lactylate.
It is also known to coat medical articles, including sutures, with metallic compounds to impart antimicrobial characteristics to the articles. The anti-microbial effects of metallic ions including Ag, Au, Pt, Pd, Ir, Cu, Sn, Sb, Bi and Zn are known (see Morton, H. E., Pseudomonas in Disinfection, Sterilization and Preservation, ed. S. S. Block, Lea and Febiger, 1977 and Grier, N., Silver and Its Compounds in Disinfection, Sterilization and Preservation, ed. S. S. Block, Lea and Febiger, 1977). Silver is one of the preferred metallic ions, due to its unusually good bioactivity at low concentrations. In modern medical practice both inorganic and organic soluble salts of silver are used to prevent and treat microbial infections. While these compounds are effective as soluble salts, they do not provide prolonged protection and must be frequently reapplied. Reapplication may not always be practical, especially where an implanted device is involved. U.S. Pat. No. 6,017,553 attempts to improve upon the use of silver as an antimicrobial agent for medical devices by creating atomic disorder during vapor deposition of the metallic antimicrobial agents.
Sutures having antimicrobial properties, that are inexpensive and can be constructed with biocompatible materials without being subject to excessive diffusion, are still desirable. This is especially so where the suture is absorbable and there is no opportunity to reapply the antimicrobial coating.